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7ee9e4405f
linux/fs/btrfs/file.c
Josef Bacik 7ee9e4405f Btrfs: check if we can nocow if we don't have data space 
We always just try and reserve data space when we write, but if we are out of
space but have prealloc'ed extents we should still successfully write.  This
patch will try and see if we can write to prealloc'ed space and if we can go
ahead and allow the write to continue.  With this patch we now pass xfstests
generic/274.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-07-02 11:50:45 -04:00

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/*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/backing-dev.h>
#include <linux/mpage.h>
#include <linux/falloc.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/statfs.h>
#include <linux/compat.h>
#include <linux/slab.h>
#include <linux/btrfs.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "print-tree.h"
#include "tree-log.h"
#include "locking.h"
#include "compat.h"
#include "volumes.h"
static struct kmem_cache *btrfs_inode_defrag_cachep;
/*
* when auto defrag is enabled we
* queue up these defrag structs to remember which
* inodes need defragging passes
*/
struct inode_defrag {
struct rb_node rb_node;
/* objectid */
u64 ino;
/*
* transid where the defrag was added, we search for
* extents newer than this
*/
u64 transid;
/* root objectid */
u64 root;
/* last offset we were able to defrag */
u64 last_offset;
/* if we've wrapped around back to zero once already */
int cycled;
};
static int __compare_inode_defrag(struct inode_defrag *defrag1,
struct inode_defrag *defrag2)
{
if (defrag1->root > defrag2->root)
return 1;
else if (defrag1->root < defrag2->root)
return -1;
else if (defrag1->ino > defrag2->ino)
return 1;
else if (defrag1->ino < defrag2->ino)
return -1;
else
return 0;
}
/* pop a record for an inode into the defrag tree. The lock
* must be held already
*
* If you're inserting a record for an older transid than an
* existing record, the transid already in the tree is lowered
*
* If an existing record is found the defrag item you
* pass in is freed
*/
static int __btrfs_add_inode_defrag(struct inode *inode,
struct inode_defrag *defrag)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct inode_defrag *entry;
struct rb_node **p;
struct rb_node *parent = NULL;
int ret;
p = &root->fs_info->defrag_inodes.rb_node;
while (*p) {
parent = *p;
entry = rb_entry(parent, struct inode_defrag, rb_node);
ret = __compare_inode_defrag(defrag, entry);
if (ret < 0)
p = &parent->rb_left;
else if (ret > 0)
p = &parent->rb_right;
else {
/* if we're reinserting an entry for
* an old defrag run, make sure to
* lower the transid of our existing record
*/
if (defrag->transid < entry->transid)
entry->transid = defrag->transid;
if (defrag->last_offset > entry->last_offset)
entry->last_offset = defrag->last_offset;
return -EEXIST;
}
}
set_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
rb_link_node(&defrag->rb_node, parent, p);
rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
return 0;
}
static inline int __need_auto_defrag(struct btrfs_root *root)
{
if (!btrfs_test_opt(root, AUTO_DEFRAG))
return 0;
if (btrfs_fs_closing(root->fs_info))
return 0;
return 1;
}
/*
* insert a defrag record for this inode if auto defrag is
* enabled
*/
int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
struct inode *inode)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct inode_defrag *defrag;
u64 transid;
int ret;
if (!__need_auto_defrag(root))
return 0;
if (test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags))
return 0;
if (trans)
transid = trans->transid;
else
transid = BTRFS_I(inode)->root->last_trans;
defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
if (!defrag)
return -ENOMEM;
defrag->ino = btrfs_ino(inode);
defrag->transid = transid;
defrag->root = root->root_key.objectid;
spin_lock(&root->fs_info->defrag_inodes_lock);
if (!test_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags)) {
/*
* If we set IN_DEFRAG flag and evict the inode from memory,
* and then re-read this inode, this new inode doesn't have
* IN_DEFRAG flag. At the case, we may find the existed defrag.
*/
ret = __btrfs_add_inode_defrag(inode, defrag);
if (ret)
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
} else {
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
}
spin_unlock(&root->fs_info->defrag_inodes_lock);
return 0;
}
/*
* Requeue the defrag object. If there is a defrag object that points to
* the same inode in the tree, we will merge them together (by
* __btrfs_add_inode_defrag()) and free the one that we want to requeue.
*/
static void btrfs_requeue_inode_defrag(struct inode *inode,
struct inode_defrag *defrag)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret;
if (!__need_auto_defrag(root))
goto out;
/*
* Here we don't check the IN_DEFRAG flag, because we need merge
* them together.
*/
spin_lock(&root->fs_info->defrag_inodes_lock);
ret = __btrfs_add_inode_defrag(inode, defrag);
spin_unlock(&root->fs_info->defrag_inodes_lock);
if (ret)
goto out;
return;
out:
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
}
/*
* pick the defragable inode that we want, if it doesn't exist, we will get
* the next one.
*/
static struct inode_defrag *
btrfs_pick_defrag_inode(struct btrfs_fs_info *fs_info, u64 root, u64 ino)
{
struct inode_defrag *entry = NULL;
struct inode_defrag tmp;
struct rb_node *p;
struct rb_node *parent = NULL;
int ret;
tmp.ino = ino;
tmp.root = root;
spin_lock(&fs_info->defrag_inodes_lock);
p = fs_info->defrag_inodes.rb_node;
while (p) {
parent = p;
entry = rb_entry(parent, struct inode_defrag, rb_node);
ret = __compare_inode_defrag(&tmp, entry);
if (ret < 0)
p = parent->rb_left;
else if (ret > 0)
p = parent->rb_right;
else
goto out;
}
if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
parent = rb_next(parent);
if (parent)
entry = rb_entry(parent, struct inode_defrag, rb_node);
else
entry = NULL;
}
out:
if (entry)
rb_erase(parent, &fs_info->defrag_inodes);
spin_unlock(&fs_info->defrag_inodes_lock);
return entry;
}
void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
{
struct inode_defrag *defrag;
struct rb_node *node;
spin_lock(&fs_info->defrag_inodes_lock);
node = rb_first(&fs_info->defrag_inodes);
while (node) {
rb_erase(node, &fs_info->defrag_inodes);
defrag = rb_entry(node, struct inode_defrag, rb_node);
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
if (need_resched()) {
spin_unlock(&fs_info->defrag_inodes_lock);
cond_resched();
spin_lock(&fs_info->defrag_inodes_lock);
}
node = rb_first(&fs_info->defrag_inodes);
}
spin_unlock(&fs_info->defrag_inodes_lock);
}
#define BTRFS_DEFRAG_BATCH 1024
static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
struct inode_defrag *defrag)
{
struct btrfs_root *inode_root;
struct inode *inode;
struct btrfs_key key;
struct btrfs_ioctl_defrag_range_args range;
int num_defrag;
int index;
int ret;
/* get the inode */
key.objectid = defrag->root;
btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
key.offset = (u64)-1;
index = srcu_read_lock(&fs_info->subvol_srcu);
inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
if (IS_ERR(inode_root)) {
ret = PTR_ERR(inode_root);
goto cleanup;
}
key.objectid = defrag->ino;
btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
key.offset = 0;
inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
if (IS_ERR(inode)) {
ret = PTR_ERR(inode);
goto cleanup;
}
srcu_read_unlock(&fs_info->subvol_srcu, index);
/* do a chunk of defrag */
clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
memset(&range, 0, sizeof(range));
range.len = (u64)-1;
range.start = defrag->last_offset;
sb_start_write(fs_info->sb);
num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
BTRFS_DEFRAG_BATCH);
sb_end_write(fs_info->sb);
/*
* if we filled the whole defrag batch, there
* must be more work to do. Queue this defrag
* again
*/
if (num_defrag == BTRFS_DEFRAG_BATCH) {
defrag->last_offset = range.start;
btrfs_requeue_inode_defrag(inode, defrag);
} else if (defrag->last_offset && !defrag->cycled) {
/*
* we didn't fill our defrag batch, but
* we didn't start at zero. Make sure we loop
* around to the start of the file.
*/
defrag->last_offset = 0;
defrag->cycled = 1;
btrfs_requeue_inode_defrag(inode, defrag);
} else {
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
}
iput(inode);
return 0;
cleanup:
srcu_read_unlock(&fs_info->subvol_srcu, index);
kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
return ret;
}
/*
* run through the list of inodes in the FS that need
* defragging
*/
int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
{
struct inode_defrag *defrag;
u64 first_ino = 0;
u64 root_objectid = 0;
atomic_inc(&fs_info->defrag_running);
while(1) {
/* Pause the auto defragger. */
if (test_bit(BTRFS_FS_STATE_REMOUNTING,
&fs_info->fs_state))
break;
if (!__need_auto_defrag(fs_info->tree_root))
break;
/* find an inode to defrag */
defrag = btrfs_pick_defrag_inode(fs_info, root_objectid,
first_ino);
if (!defrag) {
if (root_objectid || first_ino) {
root_objectid = 0;
first_ino = 0;
continue;
} else {
break;
}
}
first_ino = defrag->ino + 1;
root_objectid = defrag->root;
__btrfs_run_defrag_inode(fs_info, defrag);
}
atomic_dec(&fs_info->defrag_running);
/*
* during unmount, we use the transaction_wait queue to
* wait for the defragger to stop
*/
wake_up(&fs_info->transaction_wait);
return 0;
}
/* simple helper to fault in pages and copy. This should go away
* and be replaced with calls into generic code.
*/
static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
size_t write_bytes,
struct page **prepared_pages,
struct iov_iter *i)
{
size_t copied = 0;
size_t total_copied = 0;
int pg = 0;
int offset = pos & (PAGE_CACHE_SIZE - 1);
while (write_bytes > 0) {
size_t count = min_t(size_t,
PAGE_CACHE_SIZE - offset, write_bytes);
struct page *page = prepared_pages[pg];
/*
* Copy data from userspace to the current page
*
* Disable pagefault to avoid recursive lock since
* the pages are already locked
*/
pagefault_disable();
copied = iov_iter_copy_from_user_atomic(page, i, offset, count);
pagefault_enable();
/* Flush processor's dcache for this page */
flush_dcache_page(page);
/*
* if we get a partial write, we can end up with
* partially up to date pages. These add
* a lot of complexity, so make sure they don't
* happen by forcing this copy to be retried.
*
* The rest of the btrfs_file_write code will fall
* back to page at a time copies after we return 0.
*/
if (!PageUptodate(page) && copied < count)
copied = 0;
iov_iter_advance(i, copied);
write_bytes -= copied;
total_copied += copied;
/* Return to btrfs_file_aio_write to fault page */
if (unlikely(copied == 0))
break;
if (unlikely(copied < PAGE_CACHE_SIZE - offset)) {
offset += copied;
} else {
pg++;
offset = 0;
}
}
return total_copied;
}
/*
* unlocks pages after btrfs_file_write is done with them
*/
static void btrfs_drop_pages(struct page **pages, size_t num_pages)
{
size_t i;
for (i = 0; i < num_pages; i++) {
/* page checked is some magic around finding pages that
* have been modified without going through btrfs_set_page_dirty
* clear it here
*/
ClearPageChecked(pages[i]);
unlock_page(pages[i]);
mark_page_accessed(pages[i]);
page_cache_release(pages[i]);
}
}
/*
* after copy_from_user, pages need to be dirtied and we need to make
* sure holes are created between the current EOF and the start of
* any next extents (if required).
*
* this also makes the decision about creating an inline extent vs
* doing real data extents, marking pages dirty and delalloc as required.
*/
int btrfs_dirty_pages(struct btrfs_root *root, struct inode *inode,
struct page **pages, size_t num_pages,
loff_t pos, size_t write_bytes,
struct extent_state **cached)
{
int err = 0;
int i;
u64 num_bytes;
u64 start_pos;
u64 end_of_last_block;
u64 end_pos = pos + write_bytes;
loff_t isize = i_size_read(inode);
start_pos = pos & ~((u64)root->sectorsize - 1);
num_bytes = ALIGN(write_bytes + pos - start_pos, root->sectorsize);
end_of_last_block = start_pos + num_bytes - 1;
err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
cached);
if (err)
return err;
for (i = 0; i < num_pages; i++) {
struct page *p = pages[i];
SetPageUptodate(p);
ClearPageChecked(p);
set_page_dirty(p);
}
/*
* we've only changed i_size in ram, and we haven't updated
* the disk i_size. There is no need to log the inode
* at this time.
*/
if (end_pos > isize)
i_size_write(inode, end_pos);
return 0;
}
/*
* this drops all the extents in the cache that intersect the range
* [start, end]. Existing extents are split as required.
*/
void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
int skip_pinned)
{
struct extent_map *em;
struct extent_map *split = NULL;
struct extent_map *split2 = NULL;
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
u64 len = end - start + 1;
u64 gen;
int ret;
int testend = 1;
unsigned long flags;
int compressed = 0;
bool modified;
WARN_ON(end < start);
if (end == (u64)-1) {
len = (u64)-1;
testend = 0;
}
while (1) {
int no_splits = 0;
modified = false;
if (!split)
split = alloc_extent_map();
if (!split2)
split2 = alloc_extent_map();
if (!split || !split2)
no_splits = 1;
write_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, start, len);
if (!em) {
write_unlock(&em_tree->lock);
break;
}
flags = em->flags;
gen = em->generation;
if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
if (testend && em->start + em->len >= start + len) {
free_extent_map(em);
write_unlock(&em_tree->lock);
break;
}
start = em->start + em->len;
if (testend)
len = start + len - (em->start + em->len);
free_extent_map(em);
write_unlock(&em_tree->lock);
continue;
}
compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
clear_bit(EXTENT_FLAG_PINNED, &em->flags);
clear_bit(EXTENT_FLAG_LOGGING, &flags);
modified = !list_empty(&em->list);
remove_extent_mapping(em_tree, em);
if (no_splits)
goto next;
if (em->block_start < EXTENT_MAP_LAST_BYTE &&
em->start < start) {
split->start = em->start;
split->len = start - em->start;
split->orig_start = em->orig_start;
split->block_start = em->block_start;
if (compressed)
split->block_len = em->block_len;
else
split->block_len = split->len;
split->ram_bytes = em->ram_bytes;
split->orig_block_len = max(split->block_len,
em->orig_block_len);
split->generation = gen;
split->bdev = em->bdev;
split->flags = flags;
split->compress_type = em->compress_type;
ret = add_extent_mapping(em_tree, split, modified);
BUG_ON(ret); /* Logic error */
free_extent_map(split);
split = split2;
split2 = NULL;
}
if (em->block_start < EXTENT_MAP_LAST_BYTE &&
testend && em->start + em->len > start + len) {
u64 diff = start + len - em->start;
split->start = start + len;
split->len = em->start + em->len - (start + len);
split->bdev = em->bdev;
split->flags = flags;
split->compress_type = em->compress_type;
split->generation = gen;
split->orig_block_len = max(em->block_len,
em->orig_block_len);
split->ram_bytes = em->ram_bytes;
if (compressed) {
split->block_len = em->block_len;
split->block_start = em->block_start;
split->orig_start = em->orig_start;
} else {
split->block_len = split->len;
split->block_start = em->block_start + diff;
split->orig_start = em->orig_start;
}
ret = add_extent_mapping(em_tree, split, modified);
BUG_ON(ret); /* Logic error */
free_extent_map(split);
split = NULL;
}
next:
write_unlock(&em_tree->lock);
/* once for us */
free_extent_map(em);
/* once for the tree*/
free_extent_map(em);
}
if (split)
free_extent_map(split);
if (split2)
free_extent_map(split2);
}
/*
* this is very complex, but the basic idea is to drop all extents
* in the range start - end. hint_block is filled in with a block number
* that would be a good hint to the block allocator for this file.
*
* If an extent intersects the range but is not entirely inside the range
* it is either truncated or split. Anything entirely inside the range
* is deleted from the tree.
*/
int __btrfs_drop_extents(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode,
struct btrfs_path *path, u64 start, u64 end,
u64 *drop_end, int drop_cache)
{
struct extent_buffer *leaf;
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
struct btrfs_key new_key;
u64 ino = btrfs_ino(inode);
u64 search_start = start;
u64 disk_bytenr = 0;
u64 num_bytes = 0;
u64 extent_offset = 0;
u64 extent_end = 0;
int del_nr = 0;
int del_slot = 0;
int extent_type;
int recow;
int ret;
int modify_tree = -1;
int update_refs = (root->ref_cows || root == root->fs_info->tree_root);
int found = 0;
if (drop_cache)
btrfs_drop_extent_cache(inode, start, end - 1, 0);
if (start >= BTRFS_I(inode)->disk_i_size)
modify_tree = 0;
while (1) {
recow = 0;
ret = btrfs_lookup_file_extent(trans, root, path, ino,
search_start, modify_tree);
if (ret < 0)
break;
if (ret > 0 && path->slots[0] > 0 && search_start == start) {
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
if (key.objectid == ino &&
key.type == BTRFS_EXTENT_DATA_KEY)
path->slots[0]--;
}
ret = 0;
next_slot:
leaf = path->nodes[0];
if (path->slots[0] >= btrfs_header_nritems(leaf)) {
BUG_ON(del_nr > 0);
ret = btrfs_next_leaf(root, path);
if (ret < 0)
break;
if (ret > 0) {
ret = 0;
break;
}
leaf = path->nodes[0];
recow = 1;
}
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
if (key.objectid > ino ||
key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
break;
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
extent_type = btrfs_file_extent_type(leaf, fi);
if (extent_type == BTRFS_FILE_EXTENT_REG ||
extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
extent_offset = btrfs_file_extent_offset(leaf, fi);
extent_end = key.offset +
btrfs_file_extent_num_bytes(leaf, fi);
} else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
extent_end = key.offset +
btrfs_file_extent_inline_len(leaf, fi);
} else {
WARN_ON(1);
extent_end = search_start;
}
if (extent_end <= search_start) {
path->slots[0]++;
goto next_slot;
}
found = 1;
search_start = max(key.offset, start);
if (recow || !modify_tree) {
modify_tree = -1;
btrfs_release_path(path);
continue;
}
/*
* | - range to drop - |
* | -------- extent -------- |
*/
if (start > key.offset && end < extent_end) {
BUG_ON(del_nr > 0);
BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
memcpy(&new_key, &key, sizeof(new_key));
new_key.offset = start;
ret = btrfs_duplicate_item(trans, root, path,
&new_key);
if (ret == -EAGAIN) {
btrfs_release_path(path);
continue;
}
if (ret < 0)
break;
leaf = path->nodes[0];
fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_num_bytes(leaf, fi,
start - key.offset);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
extent_offset += start - key.offset;
btrfs_set_file_extent_offset(leaf, fi, extent_offset);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - start);
btrfs_mark_buffer_dirty(leaf);
if (update_refs && disk_bytenr > 0) {
ret = btrfs_inc_extent_ref(trans, root,
disk_bytenr, num_bytes, 0,
root->root_key.objectid,
new_key.objectid,
start - extent_offset, 0);
BUG_ON(ret); /* -ENOMEM */
}
key.offset = start;
}
/*
* | ---- range to drop ----- |
* | -------- extent -------- |
*/
if (start <= key.offset && end < extent_end) {
BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
memcpy(&new_key, &key, sizeof(new_key));
new_key.offset = end;
btrfs_set_item_key_safe(root, path, &new_key);
extent_offset += end - key.offset;
btrfs_set_file_extent_offset(leaf, fi, extent_offset);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - end);
btrfs_mark_buffer_dirty(leaf);
if (update_refs && disk_bytenr > 0)
inode_sub_bytes(inode, end - key.offset);
break;
}
search_start = extent_end;
/*
* | ---- range to drop ----- |
* | -------- extent -------- |
*/
if (start > key.offset && end >= extent_end) {
BUG_ON(del_nr > 0);
BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
btrfs_set_file_extent_num_bytes(leaf, fi,
start - key.offset);
btrfs_mark_buffer_dirty(leaf);
if (update_refs && disk_bytenr > 0)
inode_sub_bytes(inode, extent_end - start);
if (end == extent_end)
break;
path->slots[0]++;
goto next_slot;
}
/*
* | ---- range to drop ----- |
* | ------ extent ------ |
*/
if (start <= key.offset && end >= extent_end) {
if (del_nr == 0) {
del_slot = path->slots[0];
del_nr = 1;
} else {
BUG_ON(del_slot + del_nr != path->slots[0]);
del_nr++;
}
if (update_refs &&
extent_type == BTRFS_FILE_EXTENT_INLINE) {
inode_sub_bytes(inode,
extent_end - key.offset);
extent_end = ALIGN(extent_end,
root->sectorsize);
} else if (update_refs && disk_bytenr > 0) {
ret = btrfs_free_extent(trans, root,
disk_bytenr, num_bytes, 0,
root->root_key.objectid,
key.objectid, key.offset -
extent_offset, 0);
BUG_ON(ret); /* -ENOMEM */
inode_sub_bytes(inode,
extent_end - key.offset);
}
if (end == extent_end)
break;
if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
path->slots[0]++;
goto next_slot;
}
ret = btrfs_del_items(trans, root, path, del_slot,
del_nr);
if (ret) {
btrfs_abort_transaction(trans, root, ret);
break;
}
del_nr = 0;
del_slot = 0;
btrfs_release_path(path);
continue;
}
BUG_ON(1);
}
if (!ret && del_nr > 0) {
ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
if (ret)
btrfs_abort_transaction(trans, root, ret);
}
if (drop_end)
*drop_end = found ? min(end, extent_end) : end;
btrfs_release_path(path);
return ret;
}
int btrfs_drop_extents(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode, u64 start,
u64 end, int drop_cache)
{
struct btrfs_path *path;
int ret;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
ret = __btrfs_drop_extents(trans, root, inode, path, start, end, NULL,
drop_cache);
btrfs_free_path(path);
return ret;
}
static int extent_mergeable(struct extent_buffer *leaf, int slot,
u64 objectid, u64 bytenr, u64 orig_offset,
u64 *start, u64 *end)
{
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
u64 extent_end;
if (slot < 0 || slot >= btrfs_header_nritems(leaf))
return 0;
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
return 0;
fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
btrfs_file_extent_compression(leaf, fi) ||
btrfs_file_extent_encryption(leaf, fi) ||
btrfs_file_extent_other_encoding(leaf, fi))
return 0;
extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
if ((*start && *start != key.offset) || (*end && *end != extent_end))
return 0;
*start = key.offset;
*end = extent_end;
return 1;
}
/*
* Mark extent in the range start - end as written.
*
* This changes extent type from 'pre-allocated' to 'regular'. If only
* part of extent is marked as written, the extent will be split into
* two or three.
*/
int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
struct inode *inode, u64 start, u64 end)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct extent_buffer *leaf;
struct btrfs_path *path;
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
struct btrfs_key new_key;
u64 bytenr;
u64 num_bytes;
u64 extent_end;
u64 orig_offset;
u64 other_start;
u64 other_end;
u64 split;
int del_nr = 0;
int del_slot = 0;
int recow;
int ret;
u64 ino = btrfs_ino(inode);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
again:
recow = 0;
split = start;
key.objectid = ino;
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = split;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret < 0)
goto out;
if (ret > 0 && path->slots[0] > 0)
path->slots[0]--;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
BUG_ON(key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
BUG_ON(btrfs_file_extent_type(leaf, fi) !=
BTRFS_FILE_EXTENT_PREALLOC);
extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
BUG_ON(key.offset > start || extent_end < end);
bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
memcpy(&new_key, &key, sizeof(new_key));
if (start == key.offset && end < extent_end) {
other_start = 0;
other_end = start;
if (extent_mergeable(leaf, path->slots[0] - 1,
ino, bytenr, orig_offset,
&other_start, &other_end)) {
new_key.offset = end;
btrfs_set_item_key_safe(root, path, &new_key);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi,
trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - end);
btrfs_set_file_extent_offset(leaf, fi,
end - orig_offset);
fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi,
trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
end - other_start);
btrfs_mark_buffer_dirty(leaf);
goto out;
}
}
if (start > key.offset && end == extent_end) {
other_start = end;
other_end = 0;
if (extent_mergeable(leaf, path->slots[0] + 1,
ino, bytenr, orig_offset,
&other_start, &other_end)) {
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_num_bytes(leaf, fi,
start - key.offset);
btrfs_set_file_extent_generation(leaf, fi,
trans->transid);
path->slots[0]++;
new_key.offset = start;
btrfs_set_item_key_safe(root, path, &new_key);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi,
trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
other_end - start);
btrfs_set_file_extent_offset(leaf, fi,
start - orig_offset);
btrfs_mark_buffer_dirty(leaf);
goto out;
}
}
while (start > key.offset || end < extent_end) {
if (key.offset == start)
split = end;
new_key.offset = split;
ret = btrfs_duplicate_item(trans, root, path, &new_key);
if (ret == -EAGAIN) {
btrfs_release_path(path);
goto again;
}
if (ret < 0) {
btrfs_abort_transaction(trans, root, ret);
goto out;
}
leaf = path->nodes[0];
fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
split - key.offset);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - split);
btrfs_mark_buffer_dirty(leaf);
ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
root->root_key.objectid,
ino, orig_offset, 0);
BUG_ON(ret); /* -ENOMEM */
if (split == start) {
key.offset = start;
} else {
BUG_ON(start != key.offset);
path->slots[0]--;
extent_end = end;
}
recow = 1;
}
other_start = end;
other_end = 0;
if (extent_mergeable(leaf, path->slots[0] + 1,
ino, bytenr, orig_offset,
&other_start, &other_end)) {
if (recow) {
btrfs_release_path(path);
goto again;
}
extent_end = other_end;
del_slot = path->slots[0] + 1;
del_nr++;
ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
0, root->root_key.objectid,
ino, orig_offset, 0);
BUG_ON(ret); /* -ENOMEM */
}
other_start = 0;
other_end = start;
if (extent_mergeable(leaf, path->slots[0] - 1,
ino, bytenr, orig_offset,
&other_start, &other_end)) {
if (recow) {
btrfs_release_path(path);
goto again;
}
key.offset = other_start;
del_slot = path->slots[0];
del_nr++;
ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
0, root->root_key.objectid,
ino, orig_offset, 0);
BUG_ON(ret); /* -ENOMEM */
}
if (del_nr == 0) {
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_type(leaf, fi,
BTRFS_FILE_EXTENT_REG);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_mark_buffer_dirty(leaf);
} else {
fi = btrfs_item_ptr(leaf, del_slot - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_type(leaf, fi,
BTRFS_FILE_EXTENT_REG);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - key.offset);
btrfs_mark_buffer_dirty(leaf);
ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
if (ret < 0) {
btrfs_abort_transaction(trans, root, ret);
goto out;
}
}
out:
btrfs_free_path(path);
return 0;
}
/*
* on error we return an unlocked page and the error value
* on success we return a locked page and 0
*/
static int prepare_uptodate_page(struct page *page, u64 pos,
bool force_uptodate)
{
int ret = 0;
if (((pos & (PAGE_CACHE_SIZE - 1)) || force_uptodate) &&
!PageUptodate(page)) {
ret = btrfs_readpage(NULL, page);
if (ret)
return ret;
lock_page(page);
if (!PageUptodate(page)) {
unlock_page(page);
return -EIO;
}
}
return 0;
}
/*
* this gets pages into the page cache and locks them down, it also properly
* waits for data=ordered extents to finish before allowing the pages to be
* modified.
*/
static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
struct page **pages, size_t num_pages,
loff_t pos, unsigned long first_index,
size_t write_bytes, bool force_uptodate)
{
struct extent_state *cached_state = NULL;
int i;
unsigned long index = pos >> PAGE_CACHE_SHIFT;
struct inode *inode = file_inode(file);
gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
int err = 0;
int faili = 0;
u64 start_pos;
u64 last_pos;
start_pos = pos & ~((u64)root->sectorsize - 1);
last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
again:
for (i = 0; i < num_pages; i++) {
pages[i] = find_or_create_page(inode->i_mapping, index + i,
mask | __GFP_WRITE);
if (!pages[i]) {
faili = i - 1;
err = -ENOMEM;
goto fail;
}
if (i == 0)
err = prepare_uptodate_page(pages[i], pos,
force_uptodate);
if (i == num_pages - 1)
err = prepare_uptodate_page(pages[i],
pos + write_bytes, false);
if (err) {
page_cache_release(pages[i]);
faili = i - 1;
goto fail;
}
wait_on_page_writeback(pages[i]);
}
err = 0;
if (start_pos < inode->i_size) {
struct btrfs_ordered_extent *ordered;
lock_extent_bits(&BTRFS_I(inode)->io_tree,
start_pos, last_pos - 1, 0, &cached_state);
ordered = btrfs_lookup_first_ordered_extent(inode,
last_pos - 1);
if (ordered &&
ordered->file_offset + ordered->len > start_pos &&
ordered->file_offset < last_pos) {
btrfs_put_ordered_extent(ordered);
unlock_extent_cached(&BTRFS_I(inode)->io_tree,
start_pos, last_pos - 1,
&cached_state, GFP_NOFS);
for (i = 0; i < num_pages; i++) {
unlock_page(pages[i]);
page_cache_release(pages[i]);
}
btrfs_wait_ordered_range(inode, start_pos,
last_pos - start_pos);
goto again;
}
if (ordered)
btrfs_put_ordered_extent(ordered);
clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG,
0, 0, &cached_state, GFP_NOFS);
unlock_extent_cached(&BTRFS_I(inode)->io_tree,
start_pos, last_pos - 1, &cached_state,
GFP_NOFS);
}
for (i = 0; i < num_pages; i++) {
if (clear_page_dirty_for_io(pages[i]))
account_page_redirty(pages[i]);
set_page_extent_mapped(pages[i]);
WARN_ON(!PageLocked(pages[i]));
}
return 0;
fail:
while (faili >= 0) {
unlock_page(pages[faili]);
page_cache_release(pages[faili]);
faili--;
}
return err;
}
static noinline int check_can_nocow(struct inode *inode, loff_t pos,
size_t *write_bytes)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_ordered_extent *ordered;
u64 lockstart, lockend;
u64 num_bytes;
int ret;
lockstart = round_down(pos, root->sectorsize);
lockend = lockstart + round_up(*write_bytes, root->sectorsize) - 1;
while (1) {
lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
ordered = btrfs_lookup_ordered_range(inode, lockstart,
lockend - lockstart + 1);
if (!ordered) {
break;
}
unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
btrfs_start_ordered_extent(inode, ordered, 1);
btrfs_put_ordered_extent(ordered);
}
trans = btrfs_join_transaction(root);
if (IS_ERR(trans)) {
unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
return PTR_ERR(trans);
}
num_bytes = lockend - lockstart + 1;
ret = can_nocow_extent(trans, inode, lockstart, &num_bytes, NULL, NULL,
NULL);
btrfs_end_transaction(trans, root);
if (ret <= 0) {
ret = 0;
} else {
clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
EXTENT_DIRTY | EXTENT_DELALLOC |
EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0,
NULL, GFP_NOFS);
*write_bytes = min_t(size_t, *write_bytes, num_bytes);
}
unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
return ret;
}
static noinline ssize_t __btrfs_buffered_write(struct file *file,
struct iov_iter *i,
loff_t pos)
{
struct inode *inode = file_inode(file);
struct btrfs_root *root = BTRFS_I(inode)->root;
struct page **pages = NULL;
u64 release_bytes = 0;
unsigned long first_index;
size_t num_written = 0;
int nrptrs;
int ret = 0;
bool only_release_metadata = false;
bool force_page_uptodate = false;
nrptrs = min((iov_iter_count(i) + PAGE_CACHE_SIZE - 1) /
PAGE_CACHE_SIZE, PAGE_CACHE_SIZE /
(sizeof(struct page *)));
nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
nrptrs = max(nrptrs, 8);
pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
if (!pages)
return -ENOMEM;
first_index = pos >> PAGE_CACHE_SHIFT;
while (iov_iter_count(i) > 0) {
size_t offset = pos & (PAGE_CACHE_SIZE - 1);
size_t write_bytes = min(iov_iter_count(i),
nrptrs * (size_t)PAGE_CACHE_SIZE -
offset);
size_t num_pages = (write_bytes + offset +
PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
size_t reserve_bytes;
size_t dirty_pages;
size_t copied;
WARN_ON(num_pages > nrptrs);
/*
* Fault pages before locking them in prepare_pages
* to avoid recursive lock
*/
if (unlikely(iov_iter_fault_in_readable(i, write_bytes))) {
ret = -EFAULT;
break;
}
reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
ret = btrfs_check_data_free_space(inode, reserve_bytes);
if (ret == -ENOSPC &&
(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW |
BTRFS_INODE_PREALLOC))) {
ret = check_can_nocow(inode, pos, &write_bytes);
if (ret > 0) {
only_release_metadata = true;
/*
* our prealloc extent may be smaller than
* write_bytes, so scale down.
*/
num_pages = (write_bytes + offset +
PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
reserve_bytes = num_pages << PAGE_CACHE_SHIFT;
ret = 0;
} else {
ret = -ENOSPC;
}
}
if (ret)
break;
ret = btrfs_delalloc_reserve_metadata(inode, reserve_bytes);
if (ret) {
if (!only_release_metadata)
btrfs_free_reserved_data_space(inode,
reserve_bytes);
break;
}
release_bytes = reserve_bytes;
/*
* This is going to setup the pages array with the number of
* pages we want, so we don't really need to worry about the
* contents of pages from loop to loop
*/
ret = prepare_pages(root, file, pages, num_pages,
pos, first_index, write_bytes,
force_page_uptodate);
if (ret)
break;
copied = btrfs_copy_from_user(pos, num_pages,
write_bytes, pages, i);
/*
* if we have trouble faulting in the pages, fall
* back to one page at a time
*/
if (copied < write_bytes)
nrptrs = 1;
if (copied == 0) {
force_page_uptodate = true;
dirty_pages = 0;
} else {
force_page_uptodate = false;
dirty_pages = (copied + offset +
PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
}
/*
* If we had a short copy we need to release the excess delaloc
* bytes we reserved. We need to increment outstanding_extents
* because btrfs_delalloc_release_space will decrement it, but
* we still have an outstanding extent for the chunk we actually
* managed to copy.
*/
if (num_pages > dirty_pages) {
release_bytes = (num_pages - dirty_pages) <<
PAGE_CACHE_SHIFT;
if (copied > 0) {
spin_lock(&BTRFS_I(inode)->lock);
BTRFS_I(inode)->outstanding_extents++;
spin_unlock(&BTRFS_I(inode)->lock);
}
if (only_release_metadata)
btrfs_delalloc_release_metadata(inode,
release_bytes);
else
btrfs_delalloc_release_space(inode,
release_bytes);
}
release_bytes = dirty_pages << PAGE_CACHE_SHIFT;
if (copied > 0) {
ret = btrfs_dirty_pages(root, inode, pages,
dirty_pages, pos, copied,
NULL);
if (ret) {
btrfs_drop_pages(pages, num_pages);
break;
}
}
release_bytes = 0;
btrfs_drop_pages(pages, num_pages);
if (only_release_metadata && copied > 0) {
u64 lockstart = round_down(pos, root->sectorsize);
u64 lockend = lockstart +
(dirty_pages << PAGE_CACHE_SHIFT) - 1;
set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
lockend, EXTENT_NORESERVE, NULL,
NULL, GFP_NOFS);
only_release_metadata = false;
}
cond_resched();
balance_dirty_pages_ratelimited(inode->i_mapping);
if (dirty_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
btrfs_btree_balance_dirty(root);
pos += copied;
num_written += copied;
}
kfree(pages);
if (release_bytes) {
if (only_release_metadata)
btrfs_delalloc_release_metadata(inode, release_bytes);
else
btrfs_delalloc_release_space(inode, release_bytes);
}
return num_written ? num_written : ret;
}
static ssize_t __btrfs_direct_write(struct kiocb *iocb,
const struct iovec *iov,
unsigned long nr_segs, loff_t pos,
loff_t *ppos, size_t count, size_t ocount)
{
struct file *file = iocb->ki_filp;
struct iov_iter i;
ssize_t written;
ssize_t written_buffered;
loff_t endbyte;
int err;
written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos,
count, ocount);
if (written < 0 || written == count)
return written;
pos += written;
count -= written;
iov_iter_init(&i, iov, nr_segs, count, written);
written_buffered = __btrfs_buffered_write(file, &i, pos);
if (written_buffered < 0) {
err = written_buffered;
goto out;
}
endbyte = pos + written_buffered - 1;
err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte);
if (err)
goto out;
written += written_buffered;
*ppos = pos + written_buffered;
invalidate_mapping_pages(file->f_mapping, pos >> PAGE_CACHE_SHIFT,
endbyte >> PAGE_CACHE_SHIFT);
out:
return written ? written : err;
}
static void update_time_for_write(struct inode *inode)
{
struct timespec now;
if (IS_NOCMTIME(inode))
return;
now = current_fs_time(inode->i_sb);
if (!timespec_equal(&inode->i_mtime, &now))
inode->i_mtime = now;
if (!timespec_equal(&inode->i_ctime, &now))
inode->i_ctime = now;
if (IS_I_VERSION(inode))
inode_inc_iversion(inode);
}
static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct btrfs_root *root = BTRFS_I(inode)->root;
loff_t *ppos = &iocb->ki_pos;
u64 start_pos;
ssize_t num_written = 0;
ssize_t err = 0;
size_t count, ocount;
bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host);
sb_start_write(inode->i_sb);
mutex_lock(&inode->i_mutex);
err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
if (err) {
mutex_unlock(&inode->i_mutex);
goto out;
}
count = ocount;
current->backing_dev_info = inode->i_mapping->backing_dev_info;
err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
if (err) {
mutex_unlock(&inode->i_mutex);
goto out;
}
if (count == 0) {
mutex_unlock(&inode->i_mutex);
goto out;
}
err = file_remove_suid(file);
if (err) {
mutex_unlock(&inode->i_mutex);
goto out;
}
/*
* If BTRFS flips readonly due to some impossible error
* (fs_info->fs_state now has BTRFS_SUPER_FLAG_ERROR),
* although we have opened a file as writable, we have
* to stop this write operation to ensure FS consistency.
*/
if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
mutex_unlock(&inode->i_mutex);
err = -EROFS;
goto out;
}
/*
* We reserve space for updating the inode when we reserve space for the
* extent we are going to write, so we will enospc out there. We don't
* need to start yet another transaction to update the inode as we will
* update the inode when we finish writing whatever data we write.
*/
update_time_for_write(inode);
start_pos = round_down(pos, root->sectorsize);
if (start_pos > i_size_read(inode)) {
err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
if (err) {
mutex_unlock(&inode->i_mutex);
goto out;
}
}
if (sync)
atomic_inc(&BTRFS_I(inode)->sync_writers);
if (unlikely(file->f_flags & O_DIRECT)) {
num_written = __btrfs_direct_write(iocb, iov, nr_segs,
pos, ppos, count, ocount);
} else {
struct iov_iter i;
iov_iter_init(&i, iov, nr_segs, count, num_written);
num_written = __btrfs_buffered_write(file, &i, pos);
if (num_written > 0)
*ppos = pos + num_written;
}
mutex_unlock(&inode->i_mutex);
/*
* we want to make sure fsync finds this change
* but we haven't joined a transaction running right now.
*
* Later on, someone is sure to update the inode and get the
* real transid recorded.
*
* We set last_trans now to the fs_info generation + 1,
* this will either be one more than the running transaction
* or the generation used for the next transaction if there isn't
* one running right now.
*
* We also have to set last_sub_trans to the current log transid,
* otherwise subsequent syncs to a file that's been synced in this
* transaction will appear to have already occured.
*/
BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
BTRFS_I(inode)->last_sub_trans = root->log_transid;
if (num_written > 0 || num_written == -EIOCBQUEUED) {
err = generic_write_sync(file, pos, num_written);
if (err < 0 && num_written > 0)
num_written = err;
}
if (sync)
atomic_dec(&BTRFS_I(inode)->sync_writers);
out:
sb_end_write(inode->i_sb);
current->backing_dev_info = NULL;
return num_written ? num_written : err;
}
int btrfs_release_file(struct inode *inode, struct file *filp)
{
/*
* ordered_data_close is set by settattr when we are about to truncate
* a file from a non-zero size to a zero size. This tries to
* flush down new bytes that may have been written if the
* application were using truncate to replace a file in place.
*/
if (test_and_clear_bit(BTRFS_INODE_ORDERED_DATA_CLOSE,
&BTRFS_I(inode)->runtime_flags)) {
struct btrfs_trans_handle *trans;
struct btrfs_root *root = BTRFS_I(inode)->root;
/*
* We need to block on a committing transaction to keep us from
* throwing a ordered operation on to the list and causing
* something like sync to deadlock trying to flush out this
* inode.
*/
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans))
return PTR_ERR(trans);
btrfs_add_ordered_operation(trans, BTRFS_I(inode)->root, inode);
btrfs_end_transaction(trans, root);
if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
filemap_flush(inode->i_mapping);
}
if (filp->private_data)
btrfs_ioctl_trans_end(filp);
return 0;
}
/*
* fsync call for both files and directories. This logs the inode into
* the tree log instead of forcing full commits whenever possible.
*
* It needs to call filemap_fdatawait so that all ordered extent updates are
* in the metadata btree are up to date for copying to the log.
*
* It drops the inode mutex before doing the tree log commit. This is an
* important optimization for directories because holding the mutex prevents
* new operations on the dir while we write to disk.
*/
int btrfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
{
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret = 0;
struct btrfs_trans_handle *trans;
bool full_sync = 0;
trace_btrfs_sync_file(file, datasync);
/*
* We write the dirty pages in the range and wait until they complete
* out of the ->i_mutex. If so, we can flush the dirty pages by
* multi-task, and make the performance up. See
* btrfs_wait_ordered_range for an explanation of the ASYNC check.
*/
atomic_inc(&BTRFS_I(inode)->sync_writers);
ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
if (!ret && test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
&BTRFS_I(inode)->runtime_flags))
ret = filemap_fdatawrite_range(inode->i_mapping, start, end);
atomic_dec(&BTRFS_I(inode)->sync_writers);
if (ret)
return ret;
mutex_lock(&inode->i_mutex);
/*
* We flush the dirty pages again to avoid some dirty pages in the
* range being left.
*/
atomic_inc(&root->log_batch);
full_sync = test_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&BTRFS_I(inode)->runtime_flags);
if (full_sync)
btrfs_wait_ordered_range(inode, start, end - start + 1);
atomic_inc(&root->log_batch);
/*
* check the transaction that last modified this inode
* and see if its already been committed
*/
if (!BTRFS_I(inode)->last_trans) {
mutex_unlock(&inode->i_mutex);
goto out;
}
/*
* if the last transaction that changed this file was before
* the current transaction, we can bail out now without any
* syncing
*/
smp_mb();
if (btrfs_inode_in_log(inode, root->fs_info->generation) ||
BTRFS_I(inode)->last_trans <=
root->fs_info->last_trans_committed) {
BTRFS_I(inode)->last_trans = 0;
/*
* We'v had everything committed since the last time we were
* modified so clear this flag in case it was set for whatever
* reason, it's no longer relevant.
*/
clear_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&BTRFS_I(inode)->runtime_flags);
mutex_unlock(&inode->i_mutex);
goto out;
}
/*
* ok we haven't committed the transaction yet, lets do a commit
*/
if (file->private_data)
btrfs_ioctl_trans_end(file);
trans = btrfs_start_transaction(root, 0);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
mutex_unlock(&inode->i_mutex);
goto out;
}
ret = btrfs_log_dentry_safe(trans, root, dentry);
if (ret < 0) {
mutex_unlock(&inode->i_mutex);
goto out;
}
/* we've logged all the items and now have a consistent
* version of the file in the log. It is possible that
* someone will come in and modify the file, but that's
* fine because the log is consistent on disk, and we
* have references to all of the file's extents
*
* It is possible that someone will come in and log the
* file again, but that will end up using the synchronization
* inside btrfs_sync_log to keep things safe.
*/
mutex_unlock(&inode->i_mutex);
if (ret != BTRFS_NO_LOG_SYNC) {
if (ret > 0) {
/*
* If we didn't already wait for ordered extents we need
* to do that now.
*/
if (!full_sync)
btrfs_wait_ordered_range(inode, start,
end - start + 1);
ret = btrfs_commit_transaction(trans, root);
} else {
ret = btrfs_sync_log(trans, root);
if (ret == 0) {
ret = btrfs_end_transaction(trans, root);
} else {
if (!full_sync)
btrfs_wait_ordered_range(inode, start,
end -
start + 1);
ret = btrfs_commit_transaction(trans, root);
}
}
} else {
ret = btrfs_end_transaction(trans, root);
}
out:
return ret > 0 ? -EIO : ret;
}
static const struct vm_operations_struct btrfs_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = btrfs_page_mkwrite,
.remap_pages = generic_file_remap_pages,
};
static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct address_space *mapping = filp->f_mapping;
if (!mapping->a_ops->readpage)
return -ENOEXEC;
file_accessed(filp);
vma->vm_ops = &btrfs_file_vm_ops;
return 0;
}
static int hole_mergeable(struct inode *inode, struct extent_buffer *leaf,
int slot, u64 start, u64 end)
{
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
if (slot < 0 || slot >= btrfs_header_nritems(leaf))
return 0;
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid != btrfs_ino(inode) ||
key.type != BTRFS_EXTENT_DATA_KEY)
return 0;
fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG)
return 0;
if (btrfs_file_extent_disk_bytenr(leaf, fi))
return 0;
if (key.offset == end)
return 1;
if (key.offset + btrfs_file_extent_num_bytes(leaf, fi) == start)
return 1;
return 0;
}
static int fill_holes(struct btrfs_trans_handle *trans, struct inode *inode,
struct btrfs_path *path, u64 offset, u64 end)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct extent_buffer *leaf;
struct btrfs_file_extent_item *fi;
struct extent_map *hole_em;
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
struct btrfs_key key;
int ret;
key.objectid = btrfs_ino(inode);
key.type = BTRFS_EXTENT_DATA_KEY;
key.offset = offset;
ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
if (ret < 0)
return ret;
BUG_ON(!ret);
leaf = path->nodes[0];
if (hole_mergeable(inode, leaf, path->slots[0]-1, offset, end)) {
u64 num_bytes;
path->slots[0]--;
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
num_bytes = btrfs_file_extent_num_bytes(leaf, fi) +
end - offset;
btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_offset(leaf, fi, 0);
btrfs_mark_buffer_dirty(leaf);
goto out;
}
if (hole_mergeable(inode, leaf, path->slots[0]+1, offset, end)) {
u64 num_bytes;
path->slots[0]++;
key.offset = offset;
btrfs_set_item_key_safe(root, path, &key);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
num_bytes = btrfs_file_extent_num_bytes(leaf, fi) + end -
offset;
btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_offset(leaf, fi, 0);
btrfs_mark_buffer_dirty(leaf);
goto out;
}
btrfs_release_path(path);
ret = btrfs_insert_file_extent(trans, root, btrfs_ino(inode), offset,
0, 0, end - offset, 0, end - offset,
0, 0, 0);
if (ret)
return ret;
out:
btrfs_release_path(path);
hole_em = alloc_extent_map();
if (!hole_em) {
btrfs_drop_extent_cache(inode, offset, end - 1, 0);
set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&BTRFS_I(inode)->runtime_flags);
} else {
hole_em->start = offset;
hole_em->len = end - offset;
hole_em->ram_bytes = hole_em->len;
hole_em->orig_start = offset;
hole_em->block_start = EXTENT_MAP_HOLE;
hole_em->block_len = 0;
hole_em->orig_block_len = 0;
hole_em->bdev = root->fs_info->fs_devices->latest_bdev;
hole_em->compress_type = BTRFS_COMPRESS_NONE;
hole_em->generation = trans->transid;
do {
btrfs_drop_extent_cache(inode, offset, end - 1, 0);
write_lock(&em_tree->lock);
ret = add_extent_mapping(em_tree, hole_em, 1);
write_unlock(&em_tree->lock);
} while (ret == -EEXIST);
free_extent_map(hole_em);
if (ret)
set_bit(BTRFS_INODE_NEEDS_FULL_SYNC,
&BTRFS_I(inode)->runtime_flags);
}
return 0;
}
static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct extent_state *cached_state = NULL;
struct btrfs_path *path;
struct btrfs_block_rsv *rsv;
struct btrfs_trans_handle *trans;
u64 lockstart = round_up(offset, BTRFS_I(inode)->root->sectorsize);
u64 lockend = round_down(offset + len,
BTRFS_I(inode)->root->sectorsize) - 1;
u64 cur_offset = lockstart;
u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
u64 drop_end;
int ret = 0;
int err = 0;
bool same_page = ((offset >> PAGE_CACHE_SHIFT) ==
((offset + len - 1) >> PAGE_CACHE_SHIFT));
btrfs_wait_ordered_range(inode, offset, len);
mutex_lock(&inode->i_mutex);
/*
* We needn't truncate any page which is beyond the end of the file
* because we are sure there is no data there.
*/
/*
* Only do this if we are in the same page and we aren't doing the
* entire page.
*/
if (same_page && len < PAGE_CACHE_SIZE) {
if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE))
ret = btrfs_truncate_page(inode, offset, len, 0);
mutex_unlock(&inode->i_mutex);
return ret;
}
/* zero back part of the first page */
if (offset < round_up(inode->i_size, PAGE_CACHE_SIZE)) {
ret = btrfs_truncate_page(inode, offset, 0, 0);
if (ret) {
mutex_unlock(&inode->i_mutex);
return ret;
}
}
/* zero the front end of the last page */
if (offset + len < round_up(inode->i_size, PAGE_CACHE_SIZE)) {
ret = btrfs_truncate_page(inode, offset + len, 0, 1);
if (ret) {
mutex_unlock(&inode->i_mutex);
return ret;
}
}
if (lockend < lockstart) {
mutex_unlock(&inode->i_mutex);
return 0;
}
while (1) {
struct btrfs_ordered_extent *ordered;
truncate_pagecache_range(inode, lockstart, lockend);
lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
0, &cached_state);
ordered = btrfs_lookup_first_ordered_extent(inode, lockend);
/*
* We need to make sure we have no ordered extents in this range
* and nobody raced in and read a page in this range, if we did
* we need to try again.
*/
if ((!ordered ||
(ordered->file_offset + ordered->len < lockstart ||
ordered->file_offset > lockend)) &&
!test_range_bit(&BTRFS_I(inode)->io_tree, lockstart,
lockend, EXTENT_UPTODATE, 0,
cached_state)) {
if (ordered)
btrfs_put_ordered_extent(ordered);
break;
}
if (ordered)
btrfs_put_ordered_extent(ordered);
unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart,
lockend, &cached_state, GFP_NOFS);
btrfs_wait_ordered_range(inode, lockstart,
lockend - lockstart + 1);
}
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto out;
}
rsv = btrfs_alloc_block_rsv(root, BTRFS_BLOCK_RSV_TEMP);
if (!rsv) {
ret = -ENOMEM;
goto out_free;
}
rsv->size = btrfs_calc_trunc_metadata_size(root, 1);
rsv->failfast = 1;
/*
* 1 - update the inode
* 1 - removing the extents in the range
* 1 - adding the hole extent
*/
trans = btrfs_start_transaction(root, 3);
if (IS_ERR(trans)) {
err = PTR_ERR(trans);
goto out_free;
}
ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv, rsv,
min_size);
BUG_ON(ret);
trans->block_rsv = rsv;
while (cur_offset < lockend) {
ret = __btrfs_drop_extents(trans, root, inode, path,
cur_offset, lockend + 1,
&drop_end, 1);
if (ret != -ENOSPC)
break;
trans->block_rsv = &root->fs_info->trans_block_rsv;
ret = fill_holes(trans, inode, path, cur_offset, drop_end);
if (ret) {
err = ret;
break;
}
cur_offset = drop_end;
ret = btrfs_update_inode(trans, root, inode);
if (ret) {
err = ret;
break;
}
btrfs_end_transaction(trans, root);
btrfs_btree_balance_dirty(root);
trans = btrfs_start_transaction(root, 3);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
trans = NULL;
break;
}
ret = btrfs_block_rsv_migrate(&root->fs_info->trans_block_rsv,
rsv, min_size);
BUG_ON(ret); /* shouldn't happen */
trans->block_rsv = rsv;
}
if (ret) {
err = ret;
goto out_trans;
}
trans->block_rsv = &root->fs_info->trans_block_rsv;
ret = fill_holes(trans, inode, path, cur_offset, drop_end);
if (ret) {
err = ret;
goto out_trans;
}
out_trans:
if (!trans)
goto out_free;
inode_inc_iversion(inode);
inode->i_mtime = inode->i_ctime = CURRENT_TIME;
trans->block_rsv = &root->fs_info->trans_block_rsv;
ret = btrfs_update_inode(trans, root, inode);
btrfs_end_transaction(trans, root);
btrfs_btree_balance_dirty(root);
out_free:
btrfs_free_path(path);
btrfs_free_block_rsv(root, rsv);
out:
unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
&cached_state, GFP_NOFS);
mutex_unlock(&inode->i_mutex);
if (ret && !err)
err = ret;
return err;
}
static long btrfs_fallocate(struct file *file, int mode,
loff_t offset, loff_t len)
{
struct inode *inode = file_inode(file);
struct extent_state *cached_state = NULL;
struct btrfs_root *root = BTRFS_I(inode)->root;
u64 cur_offset;
u64 last_byte;
u64 alloc_start;
u64 alloc_end;
u64 alloc_hint = 0;
u64 locked_end;
struct extent_map *em;
int blocksize = BTRFS_I(inode)->root->sectorsize;
int ret;
alloc_start = round_down(offset, blocksize);
alloc_end = round_up(offset + len, blocksize);
/* Make sure we aren't being give some crap mode */
if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
return -EOPNOTSUPP;
if (mode & FALLOC_FL_PUNCH_HOLE)
return btrfs_punch_hole(inode, offset, len);
/*
* Make sure we have enough space before we do the
* allocation.
*/
ret = btrfs_check_data_free_space(inode, alloc_end - alloc_start);
if (ret)
return ret;
if (root->fs_info->quota_enabled) {
ret = btrfs_qgroup_reserve(root, alloc_end - alloc_start);
if (ret)
goto out_reserve_fail;
}
mutex_lock(&inode->i_mutex);
ret = inode_newsize_ok(inode, alloc_end);
if (ret)
goto out;
if (alloc_start > inode->i_size) {
ret = btrfs_cont_expand(inode, i_size_read(inode),
alloc_start);
if (ret)
goto out;
} else {
/*
* If we are fallocating from the end of the file onward we
* need to zero out the end of the page if i_size lands in the
* middle of a page.
*/
ret = btrfs_truncate_page(inode, inode->i_size, 0, 0);
if (ret)
goto out;
}
/*
* wait for ordered IO before we have any locks. We'll loop again
* below with the locks held.
*/
btrfs_wait_ordered_range(inode, alloc_start, alloc_end - alloc_start);
locked_end = alloc_end - 1;
while (1) {
struct btrfs_ordered_extent *ordered;
/* the extent lock is ordered inside the running
* transaction
*/
lock_extent_bits(&BTRFS_I(inode)->io_tree, alloc_start,
locked_end, 0, &cached_state);
ordered = btrfs_lookup_first_ordered_extent(inode,
alloc_end - 1);
if (ordered &&
ordered->file_offset + ordered->len > alloc_start &&
ordered->file_offset < alloc_end) {
btrfs_put_ordered_extent(ordered);
unlock_extent_cached(&BTRFS_I(inode)->io_tree,
alloc_start, locked_end,
&cached_state, GFP_NOFS);
/*
* we can't wait on the range with the transaction
* running or with the extent lock held
*/
btrfs_wait_ordered_range(inode, alloc_start,
alloc_end - alloc_start);
} else {
if (ordered)
btrfs_put_ordered_extent(ordered);
break;
}
}
cur_offset = alloc_start;
while (1) {
u64 actual_end;
em = btrfs_get_extent(inode, NULL, 0, cur_offset,
alloc_end - cur_offset, 0);
if (IS_ERR_OR_NULL(em)) {
if (!em)
ret = -ENOMEM;
else
ret = PTR_ERR(em);
break;
}
last_byte = min(extent_map_end(em), alloc_end);
actual_end = min_t(u64, extent_map_end(em), offset + len);
last_byte = ALIGN(last_byte, blocksize);
if (em->block_start == EXTENT_MAP_HOLE ||
(cur_offset >= inode->i_size &&
!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
ret = btrfs_prealloc_file_range(inode, mode, cur_offset,
last_byte - cur_offset,
1 << inode->i_blkbits,
offset + len,
&alloc_hint);
if (ret < 0) {
free_extent_map(em);
break;
}
} else if (actual_end > inode->i_size &&
!(mode & FALLOC_FL_KEEP_SIZE)) {
/*
* We didn't need to allocate any more space, but we
* still extended the size of the file so we need to
* update i_size.
*/
inode->i_ctime = CURRENT_TIME;
i_size_write(inode, actual_end);
btrfs_ordered_update_i_size(inode, actual_end, NULL);
}
free_extent_map(em);
cur_offset = last_byte;
if (cur_offset >= alloc_end) {
ret = 0;
break;
}
}
unlock_extent_cached(&BTRFS_I(inode)->io_tree, alloc_start, locked_end,
&cached_state, GFP_NOFS);
out:
mutex_unlock(&inode->i_mutex);
if (root->fs_info->quota_enabled)
btrfs_qgroup_free(root, alloc_end - alloc_start);
out_reserve_fail:
/* Let go of our reservation. */
btrfs_free_reserved_data_space(inode, alloc_end - alloc_start);
return ret;
}
static int find_desired_extent(struct inode *inode, loff_t *offset, int whence)
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct extent_map *em;
struct extent_state *cached_state = NULL;
u64 lockstart = *offset;
u64 lockend = i_size_read(inode);
u64 start = *offset;
u64 orig_start = *offset;
u64 len = i_size_read(inode);
u64 last_end = 0;
int ret = 0;
lockend = max_t(u64, root->sectorsize, lockend);
if (lockend <= lockstart)
lockend = lockstart + root->sectorsize;
lockend--;
len = lockend - lockstart + 1;
len = max_t(u64, len, root->sectorsize);
if (inode->i_size == 0)
return -ENXIO;
lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend, 0,
&cached_state);
/*
* Delalloc is such a pain. If we have a hole and we have pending
* delalloc for a portion of the hole we will get back a hole that
* exists for the entire range since it hasn't been actually written
* yet. So to take care of this case we need to look for an extent just
* before the position we want in case there is outstanding delalloc
* going on here.
*/
if (whence == SEEK_HOLE && start != 0) {
if (start <= root->sectorsize)
em = btrfs_get_extent_fiemap(inode, NULL, 0, 0,
root->sectorsize, 0);
else
em = btrfs_get_extent_fiemap(inode, NULL, 0,
start - root->sectorsize,
root->sectorsize, 0);
if (IS_ERR(em)) {
ret = PTR_ERR(em);
goto out;
}
last_end = em->start + em->len;
if (em->block_start == EXTENT_MAP_DELALLOC)
last_end = min_t(u64, last_end, inode->i_size);
free_extent_map(em);
}
while (1) {
em = btrfs_get_extent_fiemap(inode, NULL, 0, start, len, 0);
if (IS_ERR(em)) {
ret = PTR_ERR(em);
break;
}
if (em->block_start == EXTENT_MAP_HOLE) {
if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
if (last_end <= orig_start) {
free_extent_map(em);
ret = -ENXIO;
break;
}
}
if (whence == SEEK_HOLE) {
*offset = start;
free_extent_map(em);
break;
}
} else {
if (whence == SEEK_DATA) {
if (em->block_start == EXTENT_MAP_DELALLOC) {
if (start >= inode->i_size) {
free_extent_map(em);
ret = -ENXIO;
break;
}
}
if (!test_bit(EXTENT_FLAG_PREALLOC,
&em->flags)) {
*offset = start;
free_extent_map(em);
break;
}
}
}
start = em->start + em->len;
last_end = em->start + em->len;
if (em->block_start == EXTENT_MAP_DELALLOC)
last_end = min_t(u64, last_end, inode->i_size);
if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
free_extent_map(em);
ret = -ENXIO;
break;
}
free_extent_map(em);
cond_resched();
}
if (!ret)
*offset = min(*offset, inode->i_size);
out:
unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
&cached_state, GFP_NOFS);
return ret;
}
static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file->f_mapping->host;
int ret;
mutex_lock(&inode->i_mutex);
switch (whence) {
case SEEK_END:
case SEEK_CUR:
offset = generic_file_llseek(file, offset, whence);
goto out;
case SEEK_DATA:
case SEEK_HOLE:
if (offset >= i_size_read(inode)) {
mutex_unlock(&inode->i_mutex);
return -ENXIO;
}
ret = find_desired_extent(inode, &offset, whence);
if (ret) {
mutex_unlock(&inode->i_mutex);
return ret;
}
}
if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
offset = -EINVAL;
goto out;
}
if (offset > inode->i_sb->s_maxbytes) {
offset = -EINVAL;
goto out;
}
/* Special lock needed here? */
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_version = 0;
}
out:
mutex_unlock(&inode->i_mutex);
return offset;
}
const struct file_operations btrfs_file_operations = {
.llseek = btrfs_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
.aio_read = generic_file_aio_read,
.splice_read = generic_file_splice_read,
.aio_write = btrfs_file_aio_write,
.mmap = btrfs_file_mmap,
.open = generic_file_open,
.release = btrfs_release_file,
.fsync = btrfs_sync_file,
.fallocate = btrfs_fallocate,
.unlocked_ioctl = btrfs_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = btrfs_ioctl,
#endif
};
void btrfs_auto_defrag_exit(void)
{
if (btrfs_inode_defrag_cachep)
kmem_cache_destroy(btrfs_inode_defrag_cachep);
}
int btrfs_auto_defrag_init(void)
{
btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
sizeof(struct inode_defrag), 0,
SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
NULL);
if (!btrfs_inode_defrag_cachep)
return -ENOMEM;
return 0;
}
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